"A chain is as strong as its weakest link." Thus if you think electronic
connectors for products and systems are less important than what they
connect--think again. And with electronics becoming smaller, lower in power, and
higher in frequency (speed), the performance and durability, as well as cost and
time-to-market, of the connectors lynch-pinning components together gain
importance.
Playing with the big boys. Keeping good contacts with a
customer, particularly when that company is a key industry player, requires
quick reflexes to meet specific needs and the ability to meet large orders. A
prime example is found in the mid-1998 introduction of Intel's XeonTM
microprocessor. While the computer world focuses on performance, usually little
attention is paid to a reliable, cost-effective edgecard connector that permits
the microprocessor it mounts to be used. Molex (Lisle, IL), selected by Intel as
exclusive Xeon edgecard connector source, did its homework.
According to Jim McGrath, Molex strategic product manager, the company
formulated the concept and began development in late 1992 for what is today the
High Speed Edge Card (HiSpecTM) for Slot 2, as Intel calls its Xeon
applications. In early 1994 the connector configuration was shown to Intel. Two
years later, the chip maker approached Molex for a 330-contact version that
would service the Xeon. Currently 40 manufacturers are incorporating Xeon in
their computers.
Finding a material that could fill the mold of the required length was key,
says Rich Nelson, Molex engineering manager. High-temperature liquid crystal
polymers (LCP) are known for dimensional stability, thin-wall capability, and
insulation properties. "We had worked in partnership with our supplier, Ticona
(Summit, NJ) on an LCP with a 50% improvement in linear length of flow for
complete and consistent connector-mold filling," he notes. This material was
developed for even longer connectors--while costing less than previous
polymers--and so Molex had it ready for Intel's needs.
Next, meeting Intel's electrical requirements was paramount for the
tight-pitch connector. These included:
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Higher-current (>0.5A) contacts
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Short signal rise times, (&500 ps for signals faster than 200 MHz)
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Contact signal cross talk under 10%
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Low inductance (&10nH) and impedance (&50V) performance
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Maintain existing manufacturing tolerances and production methods
Tall order. Molex calls the patented result complementary
contacts--three different contacts within the connector, featuring large
power/ground contacts and smaller ones to carry signals--rather than a single
contact configuration whose individual functions can be different (see diagram).
Physically tallest are the power contacts that carry up to 1A, double their
target performance. The others are two different heights of signal connections.
The difference in height allows staggering the mating pads on the inserted
daughter card at three distinct distances from the card edge.
With three contact heights, only a third of the densely packed contacts are
displaced for mating at any one time during processor-board insertion, keeping
the overall insertion force reasonable. The connector can also withstand 50
connect/disconnect cycles--more than double that of previous versions.
Finally, McGrath notes metal for the connector contacts themselves required
tailoring to improve conductivity and allow maximum mating area. Molex worked
with suppliers Waterbury Rolling Mills (Waterbury, CT) and Olin (East Alton, IL)
to develop a palladium nickel-plated copper-based 633 alloy contact with lower
resistance than conventional phosphor bronze contacts--while having the same
price and mechanical properties and manufacturability. When stamping out the
pre-plated contacts from 0.010-inch thin sheets of the new material, its
characteristics allow maximum shearing action by the cutting tool, producing a
large, smooth contacting surface which forms the mating area. Rough areas,
having minimal contact points, developed as a tool breaks through the sheet, are
minimized.
Molex also provides other Slot 2 platform products, a voltage-regulation
module socket and a terminator card. The latter goes into unused HiSpec slots to
dissipate electronic reflections on the processor bus.
Details, details. Such wide integration efforts are often
augmented in the connector world by sometimes seemingly simple attention to
details. Revisiting a proven design often leads to leaps in functionality or a
drop in cost. Take the case with AMP's (Harrisburg, PA) V.35 connectors for
networking and data transmission applications. The most recent model of the
board-mount version of this connector has two one-piece diecast boardlocks to
secure it to a PCB before soldering. Current versions have five pieces forming
each boardlock (see photo). The ease of assembly resulted in a 10-20% lower
price with a drop-in replacement, according to product manager Anna DiRocco.
She notes many competitors and small demand growth have resulted in price
erosion for such boardmount connectors. AMP decided to reduce fabrication costs
of the connector in order to meet customer demand for lower prices yet still
maintain reasonable profitability. "A one-piece boardlock would reduce the cost,
allowing AMP to be competitive and meet customers' quality and price
requirements," DiRocco adds.
Another example of attention-to-detail chopping costs is Phoenix Contact's
(Harrisburg, PA) new PCB edge connector for motor and drive uses. This
COMBICON-Edge plug eliminates the need for a mating header block on the PCB
board. "A few key customers were getting hammered with the cost of their PCBs,"
says Product Assistant Todd Desso. "What we did was take edge connectors into
power connection blocks, lowering the cost of the product."
Desso adds the card-edge power contacts, capable of more than 10A, are
shrouded by the connector, but in a low-cost configuration. A snap-action sprung
engagement latch holds the connector to the board. Spring cages in the back of
the connector block further quicken stripped-wire installation, while retaining
contact integrity. Finally, inventory expenses are reduced since the basic
connector unit is a single-wire position block.
Thus, like a cool jazz band, those companies that work closely with
customers, listening to needs--with a good dose of improvisional, innovative
thinking--produce harmonizing results that benefit all players and the paying
customers.
When the customer is not the user
A unique challenge: design products that will be used by someone other than
the customer. Such is the case in home-telecommunications where systems may be
bought by a service provider who in turn supplies these to its subscribers. One
example: a network-interface device (NID), most commonly thought of as the
"phone box," where telecom utilities are connected to a residence's subscribers.
Since deregulation in the 1980s, the NID box has served as a demarcation/test
point where repairs have been designated within or without the home, with
subsequent responsibility for repair placed on the resident or the utility. For
testing, a resident often removes the residence-side circuit modular-plug
connection to the outside phone line in the box and directly mates his or her
phone plug into the jack to perform an integrity check. Sometimes the subscriber
forgets to remate the circuit plug after testing, resulting in a time-- and
money-- consuming "truck roll" for a false service call.
AMP Global Communication Service Providers Group's (Winston-Salem, NC)
"slimline NID" addresses test and other issues for ease of installers and
maintainers, as well as subscribers, according to Product Manager Bill Hurdle.
Telecommunication craftspeople gave input to the design, which also resulted in
a telephone-company (telco) management-pleasing cost-effective package.
The slimline device uses the latest mod jack, which has normally closed
contacts that establish an operational line without having to have a mod plug
inserted. It is only when a subscriber inserts a phone's mod plug for testing
that the circuit contacts are pushed open for the test duration. They
automatically close when the plug is removed, insuring connection
re-establishment. Hurdle says, while not speaking for the phone companies, "It
would seem the ubiquitousness of the modular outlet is approaching that of the
power outlet. The general feeling is that if the customer cannot use a modular
connection system, they will have to get help from a neighbor or pay for a
service call."
Other NID features include a completely inclosing gasket seal (made of an
AMP-developed polybutylene) around the cover. This also conforms to any wire or
cables entering the box, eliminating the need for specific grommet seals, and
forms a flood-proof seal and insect barrier. Such critters spin webs that
collect moisture-producing circuit intermittents. A block of sealant inside the
cover closes over the mod plug test jacks, keeping them clean. In the NID's
phone company-accessed section, insulation-displacement pivoting connectors
drive contacts through surrounding insulation into conductor strands. This
method replaces screw-down binding posts for tool-less, quick installation with
no contact loosening due to thermal cycling.
AMP is also developing a similar product for local exchange service. Here a
user selects or changes a service provider by merely inserting a plug into a
choice of jacks available in the box, not just phone service but Internet and
other telecommunications. As for what customers really want, Hurdle says, "In
general, the telcos have very strong opinions about what is acceptable for their
customers. This tends to vary greatly between telcos. We constantly communicate
with these individuals" for a knowledge base of positions and attitudes.
For more information
Call 1-800-828-6344, 3011 and key in the specific product code below or
circle the number on the Reader Service Card:
Connectors from Molex:
Product Code
4505
Polymers by Ticona:
Product Code 4506
Metals from Waterbury Rolling Mills:
Product Code 4507
Metals by Olin:
Product Code
4508
Connectors from AMP:
Product Code
4509
Connectors by Phoenix
Contact:
Product Code 4510 or Circle 550
Supplier Directory
In addition to the firms mentioned above, here is a sampling of some of
the other connector players. Consult your 1999 Design News OEM Directory for a
complete listing of vendors.
Elco connector systems:
Product Code
4511
Erni Components:
Product Code
4512
Harting Elektronik:
Product Code
4513
Lemo USA:
Product Code
4514
Methode Electronics:
Product Code
4515
Panduit:
Product Code
4516
Thomas & Betts:
Product Code
4517
3M:
Product Code
4518
Wieland:
Product Code
4519
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